The above-described porous aluminum sintered compact is used as electrodes and current collectors in various batteries; parts of heat exchangers; sound deadening parts; filters; shock-absorbing parts; and the like, for example.
Conventionally, these porous aluminum sintered compacts are produced by methods disclosed in Patent Literatures 1 to 5 (PTLs 1 to 5), for example.
In PTL 1, a porous aluminum sintered compact is produced as explained below. First, a mixture formed by mixing an aluminum powder; paraffin wax grains; and a binder, is shaped into a sheet-shaped form and then, subjected to natural drying. Then, the wax grains are removed by dipping the dried sheet in an organic solvent. Then, the sheet is subjected to drying, defatting, and sintering to obtain the porous aluminum sintered compact.
In PTLs 2-4, porous aluminum sintered compacts are produced by forming viscous compositions by mixing aluminum powders, sintering additives including titanium, binders, plasticizers, and organic solvents; foaming after shaping the viscous compositions; and then heat-sintering under a non-oxidizing atmosphere.
In PTL 5, a porous aluminum sintered compact is produced by mixing a base powder made of aluminum, an Al alloy powder including a eutectic element for forming bridging, and the like; and heat-sintering the obtained mixture under a hydrogen atmosphere or in a mixed atmosphere of hydrogen and nitrogen. The porous aluminum sintered compact has a structure in which grains of the base powder made of aluminum are connected each other by bridge parts made of a hypereutectic organization.